1. Technical Field
The present invention relates to craft, in particular water craft, ballast systems and systems for the rapid filling and emptying of ballast systems.
2. Description of the Related Art
In many water borne activities, water crafts, such as jet boats and rescue craft, are used to move people and/or objects across the water. The agility and power of such smaller vessels make them attractive for water-sports enthusiasts and thrill-seekers, for example. However, they may be generally unsuitable for military use as they may not be adapted for long deployment, nor be adapted to cope with the various weather conditions prevalent at sea.
The speed at which smaller craft can travel makes them comparatively less stable than larger craft, such as navy frigates and destroyers, especially in rough water. As a craft increases its velocity, the chance it will capsize can increase. This is particularly the case for jet boats and other forms of speed boat, and the capsized craft can be very difficult to ‘right’—return to an upright position—in order to continue moving.
Devices have been designed to improve the stability of the craft in the water, such as canting keels, which comprise a torpedo shaped ballast body at the tip of an aerofoil. The moment of the ballast body on the aerofoil is generally greater than that of the craft, and capsizing is thereby prevented. However, when travelling normally, the ballast is a deadweight which slows the craft, and such designs are generally impractical for use in faster boats, such as jet boats, as they reduce the speed and agility which make those craft attractive to use. Few practical designs are capable of preventing capsizing.
It is, therefore, generally desirable to provide a craft that is capable of righting.
Furthermore, it is generally desirable to overcome or ameliorate one or more of the abovementioned difficulties, or at least provide a useful alternative.